Simultaneously, in order to calculate the loudness of the alert tones, digital recordings will be obtained using two microphones located near the subject. These digital recordings will be analyzed, and a loudness value will be calculated. The loudness value is a calculated index, devised by Medtronic, which incorporates frequency and intensity. Data analysis will include a correlation between loudness value and patient characteristics, and between loudness value and ability of subjects to perceive the tones.